Micrometer



Fgb. 15, 1927.

1 1,611443v E. A. ERICKSON ET AL MIcnoMETER Fired Jan. 3'0, i925 F IE .l

WVM/70K V ployed for the purpose of providing a mi- Patented Feb; 15,1927,

nnnnsr A. nnicxson, or wILs on, `Ann zaaien .n NEAL, or wns'ijnniznnrrr,PENNSYLvAN-rn. f y

MIGROMETEl-t.

Application filed January This invention .relates to micrometers vandmoreparticularly to an attachment for use with standard insidemicrometeis.v

Various devices vhave heretofore been em- Aadvantage by adapting'anordinary inside micrometer to outside measurements and an object of ourinvention is to provide an at-v tachment for use with an ordinary insidemicrometer by means of wlifch the latter can be used to make outsidemeasurements. In the use of such a device it will frequently 'benecessary to use extension rods in making measurements and a furtherobject of this invention is to provide a device of the type set forthhaving a steady rest which may be used for supporting such an extensionrod at the desired point.

A still further object is to provide an attachment for the purpose setforth which will be simple and cheap to manufacture, rugged inconstruction and simple and accurate in operation.d

In the accompanying drawings, Figure 1,

is a view in side elevation of an' instrument embodying one forni ofthis invention; Fig. 2 1s a top plan view thereof; and, Fig. 3 is avertical sectional View on the line of Fig. 1. i l

The illustrated embodiment of this invention consists of a U-sliapedfame 5 pro vided with the usual form of anvil member 6 at the extremityof one of the arms there-V of. The other arm of the frame isprovidedwith a cylindrical bore 7 which is in axial alignment with the anvilmember 6. 'A stop screw S is threaded into the arm so as to extend intothe bore v7 any desired distance and the inner face of this screw formsa mastering or positioning point for an inside micrometer in makingmeasurements.

. The bore 7 is adapted to receive the barrel 9 of any usual form ofinside micrometer so, 1925. Y serial 150.55339.

10,y such as is ordinarily sold'onthe niai'ket, and the latter is`se'curelyzheld inplace by means otra iset screw; llextendinginto thebore through one wall thereof. l

Obviously sucli 4a device provides Aan .extremely simple means ofobtainingvoutside measurements by Imeans .of anoidinaryins'demicrometer. v Y,

lnl use it may befound` necessaryto use extension rods 12 suchl asarewelljknown in this particular art. ln .order to ,provide suiiei ent rigid itv to insure nccuratemeasure-V yments wepreferablysupport ,theextension rodloyineans of asteadyrest lfhavinggan eye 14 through whichVthe rod cextends; ln order to secure ,thesteady ,restY in yadjustedposition a flange 15 extends laterally awayfl from the base of theU-shaped `frame and is provided with inwardly extending notches 16 inwhich the steady rest is securelyfas tened by means of a nut 17 threadedto the bottom thereof for the purpose of clamping the flange 15 againsta collar 18 formedV on the steady rest. f i l By providing a pluralityof slots the rest is adapted to be positioned at lthat'point along thevextension rod at which it will provide the most rigid support, and theflange 15 must, of course, be at such an angle as to be at right 'anglesto a line drawnron the axis of the extension rod.L The steady,y

rest can be moved along the rod merely by` swinging it out `of'one ofthenotches 16 as shown in dotted lines in Fig, 3. i

Assuming that outside measurements are' to bel taken, a standard insidemicrometer is. secured in thebore 7 by clamping the set. screw 11 ontherbarrel of the micrometer inA such a position Ythat the stationaryanvil 19 of themicrometer engages the inner face of the set screw 8,7thelatter having. been posi- Y tioned so as' to form a. mastering point-forproperlyV positioning the insidev micrometer with relation to the 'anvil6. In making settings the inside micrometer head Vis'operated to fobtainthe adjustments. On account of thebarrel being fastened and .mastered tothe frame, the micrometer screw is operatedin the reversed manner fromthe usual prac-k tice. l

If the distance betweenthe master k.point and the anvil 6 is fourteeninches,'to make v a reading'of six andone-Vquarter inches, the' latterVsum is subtracted from fourteen@ Y inches, and the remainder, seven andthreequarters inches, is the setting O'v the inside micrometer; In'otherWords it the distance between theV mastering point and the anvil 6 isfourteenV inches, a micrometer setting of seven andthree-quarters inchesWill give an V'outside reading between the extension rod 12 and theanvil 6 Voi six and one-quarter inches.

Te claim: p 1. `The combination With a standard inside micrometer of aU-shaped frameV having an anvilV mounted in one arm thereof and a borein the opposite arm in axial alignment With "said anvil, means forming amastering point associated With said bore and means for securing aninside micrometer in said bore .with one o'f'itsanvils in engagementWith n an anvil mounted in one arm thereof 'anda Y bore Lin the oppositearm lin axial alignment I With said anvil, a threaded rodassociated withsaid bore so as to form a mastering standard in point and means forsecuring said inside micrometer in said bore With one of its anvils inengagement with said mastering point whereby the other anvil of saidmierometer is adapted to cooperate vWith the anvil in said trame to makeoutside'measure-y ments. Y

3. The combination with an Yinside/'niilerometei of a `til-shaped framehaving an anvil mounted therein and a bore in axial alignment with andspaced from said anvil,

means Yiter mounting said inside micrometer in predetermined ypositionin said'bore for cooperating With said anvil to malte outsidemeasurements, an extension rod associated with said' micrometer, a angeVhaving a plu; rahty of sots on said frame beneath said rod, aVsteady-rest and means tor seen-ing Vsaid steady rest in any; of theslots of said flange for supporting'said rod at any desired point. s

lil-'testimony whereof, We have hereunto set'oui' names this 27th dayofY January,

ERNEST A. ERICKSON.

Y ZEARL E. NEAL.V

